Manufacture of artificial threads



Aug. 3, 1937'. E. HUBERT ET AL MANUFACTURE OF ARTIFICIAL THRE A DS a Sheets- Sheet 1 Filed April 30, 1935 In ven fors By AfforneyS m flak/yr Aug. 3, 1937.

E. HUBERT'ET AL MANUFACTURE OF ARTIFICIAL THREADS Filed April 50, 1935 s Shets-Sheet 2 I lmkenfo'rs: 7 MM, Afforney 6%,

1937. E. HUBERT ET AL 2,088,858

MANUFACTURE OF ARTIFICIAL THREADS Filed April 50, 1935 3 Sheets-Sheet 3 Inventors:

By Affarneys Patented Aug. 3, 1937 MANUFACTURE OF ARTIFICIAL THREADS Emil Hubert, Dessau-Ziebigk, and Hans Danncnberg, Dessau, Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankforton-the-Main, Germany ,Application April 30, 1935, Serial No. 19,106

In Germany March 9, 1933 2 Claims.

Our I present. invention relates to the art of manufacturing artificial threads.

. It is a. continuation-in-part of our co -pending application Ser. No. 714,721, filed March 8, 1934. One of its objects is to provide a new process of manufacturingartificial silk and more particularly to a new process of assembling spun threads to an efficient package or cake for further treatment. Another object is the package of threads obtained by our new process. Further objects will be seen from the detailed specification following hereafter. Reference is made to the accompanying drawings in which: Figs. 1 and 1a. illustrate the spinning process, @Figs. 2, 3 and 4 show the manner in which the thread is deposited, and Figs; 5 and 6show conventional views of a finished package or cake.

L It is known to produce artificialsilk by causing athread spun in the usual. way into a spinning bath and drawn off by a roller rotating at the required speed of draftto fall freely into a slowly rotating box in which the threads are collected. In this. process a regular deposition of the thread within the box is realized by imparting to the boxa revolvingand a reciprocating movement. In this manner the threads are piled cross-wise in the form of looseloops, which, when the box is filled, are reeled ofi from the box to form hanks which may be after-treated in this form.

As artificial silk, in many cases, is no longer delivered to the consumer by the manufacturer in the form of hanks, but in a wound form, it is no longer desirable to after-treat artificial silk in hank-form. The actual state of art, for avoiding any superfluous operation, requires the filaments to be after-treated in the form in which they were spun. This is not possible with the loose layers of threads, such as they are produced in slowly rotating spinning pots as described- .The loose. layers sufier so much relative displacement by the washing and aftertreating ,liquids that reeling ofi the content of the spinning pot becomes impossible in most cases. ;In many cases the threads are rendered highly unfit for winding.

According to this invention we have found that it is possible to pile up the spun thread in form of a solid cake capable of retaining its form in (or. 1s-54 handling it in the washing and after-treatment operations and which needs no support at all neither during its production nor in handling it as aforesaid. The cake produced in this manner may be washed and after-treated in the same way as a centrifugal cake, while freely lying on a plate, or hanging on rods or arranged in any suitable manner, Without incurring displacement of the threads or impairing their capacity of being wound.

The improvement is attained in the following way:

Referring to Fig. 1, the thread I issuing from the nozzle 2 and coagulated in the spinning bath 3 is guided around the roller 4 and the thread falls from the roller 4 on the plate 5, which performs a rotary movement and an additional movement, for instance a reciprocating or an eccentric movement. The ratio between the period of the rotary movement and the period of the additional movement must be so adjusted that thelayers of threads deposited on the plate form a regular system of crossings in which each thread has its determined position. It is particularly advantageous to Wind the threads in such amanner that the windings lie closely side by side at a distance of about 2 to 5 mm. from each other. Fig. 3 shows the form of the windings which are deposited closely to each other and are helically piled up to form the cake.

Under these conditions the layers of thread form a body occupying a minimum of space and the cake being therefore very solid. In other words, the package, of threads conserving its form in the usual treatment with liquid is obtained according to thepresent invention by a method of winding the threads so as to save space. Fig; 4 shows for instance, diagrammaticallythe crossing of the thread in one layer. This figure has been obtained by covering with a paper a rotating plate to which an additional reciprocating movement has been imparted by a planetary gear and pressing a writing device, for instance, a pencil against the paper.

In order to obtain a completely unobjectionable package of threads two further conditions must be considered. The first condition is that the additional movement of the plate must not be too quick. Preferably the additional movement corresponds approximately with two revolutions of the plate that is to 'say one reciprocation must occur on somewhat more or less than two revolutions of the plate in which case the thread is deposited on the plate in double loops as shown in Fig. 2. If one reciprocation would occur on exactly one revolution or a whole number of revolutions an unserviceable cake or no cake at all is formed because in this case all loops would be deposited at the same place. The highest admissible speed is that at which one reciprocating movement takes place on every half turn of the plate. If the reciprocating additional movement is slower than the speed of the plate the thread is deposited on the plate in form of loops having a curvature which always appears concave when viewed from the center of the cake. If the reciprocating additional movement is quicker there are formed loops having varying curvature in such a manner that the curvature of the loops when viewed from the center of the cake alternately appears convex and concave. This form of loop is not favorable and yields-unserviceable' cakes when the reciprocating movement is quicker than the above mentioned limit of more than one reciprocation on half a revolution. A too quick reciprocating movement involves the 'further difficulty that the thread is no longer capable to follow the movement of the support with the required accuracy; in this case the thread comes not to lie at the intended place so that only a loose accumulation ofthreads occurs.

The second condition which must be considered for the production of an unobjectionable package of threads, is to stabilize the pendulum swingings which invariably occurs at the freely hanging part of the thread. The cause for this swinging will now be explained with reference leaves the roller.

to Fig. 2. The freely hanging thread is received by the plate 5 at 6, the speed of the thread being equal to the peripheral speed of point 6. However, by the additional movement the thread is guided alternately outwards, towards thepath of point 1, and inwards, towards the path of point 8. Points 1 and 8 however, run at a higher and a, lower speed than point 6. therefore, falls on a support which is moved alternately more swiftly and more slowly than the constant speed, at which the thread is supplied and, therefore, the thread is alternately pulled along or pushed back. The hanging thread, therefore, does not move on the path between the points I and 8, but, for instance, on the path between the points 9 and I0. Therefore the thread performs considerable pendulum swingings about the point H (see Fig. 1) at which the thread In consequence the additional movement is the cause of these pendulum swingmgs.

As it has been found these pendulum swingings cause troubles only when taking an irregular course. In this case the winding system becomes less accurate. Furthermore, the thread easily forms small loops 'or knots or is deposited across the packages at its points of reversion. Com; pletely uniform oscillations, however, do not interfere with the accuracy of the windings. The production of such uniform oscillations was realized by profiting of the resonance phenomena, which as is known occurs with any kind of oscillation. The free part of the thread which oscillates has a natural oscillation which depends on the weight of the thread, on the weight of the portions of the spinning bath adhering to the thread and on its dimensions. If the time of the natural oscillation corresponds with the period The thread,

of the additional movement of the rotating plate that is with the time of one reciprocation, resonance between the two is produced that is to say the thread oscillates uniformly and quickly without trembling or shaking and the formation of a regularly wound and solid cake occurs. Resonance is also produced if the time of oscillation and the time of revolution are in a ratio of 1:2, 1:3, 2:1, etc., that is to say in the case of a socalled harmonic.

The adjustment of the apparatus to produce resonance is very simple in practice. With a given titer and a given number of revolutions the distance between the galette and the rotary plate is varied until the oscillations have become stable, a fact which may be recognized without difliculty because in this case the thread shows neither trembling nor shaking. For making slight corrections, it'suifices to shift the point H .in Fig. l, at which the thread leaves the guide roller, in lateral direction.

The I mechanism preferably adopted in the process according to the present invention for imparting to the spinning box both a reciprocating and a rotary movement about its shaft is the planetary gear describedin our'co-pending application Ser. No. 714,720, filed March 8, 1934. However, on principle,any device for executing a rotary movementand an additional reciprocating movement subject to the above condition is suitable for use with the rotary plate for depositing threads.

The process of producing artificial silk according to this invention involves furthermore the advantage that the spinning speed can be raised to meters per minute up to meters and even more. 1

If spinning is conducted at a high rate with the customary spinning baths and the thread is collected with cross-winding on a bobbin or in a centrifugal box inknown manner, it is found that the uniformity of theartificial silk thus made is unsatisfactory, this'being particularly evidentin that the fibres are dyed very unevenly. Variations inthe composition of the spinning bath or in the length 'of travel of the thread through the bath or in both do not sufiice to provide a uniform artificial silk, particularly one which is capable of being dyed evenly and is suitable for working into fabrics It has'been found that the cause of this lack of uniformity is to be'found in the reciprocatory device which usually serves for laying the freshly spun thread in cross-wound layers on the bobbin or in the centrifugalbox, in order that it may be subjected to an after-treatment with liquids. The reciprocatory device moves the thread backwards and forwards with the aid of a threadguide (an eye, back or spinning funnel), whereby it is impossible to avoid subjecting the thread to jerksf At low and moderate spinning speeds these jerks remain within endurable limits but they increase very rapidly at higher speeds of spinning (about 90 meters per minute) and then give rise to the aforesaid lack of uniformity.

It may alsofb'e mentioned that spinning machines having a reciprocatorydevice naturally run less smoothlywhen they are operated at spinning speeds above'9O meters per minute; the oscillations thus'caused are likewise communicated tothe silk and influence, the uniformity of the final product. i

In, accordance with the present invention it is possible to produce artificial silk which does not suffer from the aforesaid objection even with a spinning speed exceeding 90 meters per minute, if the thread,'after it has been coagulated in a suitable manner, is led to the winding device without the assistance of a thread-guide or spinning funnel. For this purpose there may be used asthe winding device a support having the form of a plate, which executes a combined rotary and reciprocatory motion. This support is actuated most advantageously by means of a planetary drive. The thread which falls freely from a roller on to the support is caused by the rhythmic movement of the latter to execute pendulous oscillation, which replace the action of the reciprocating thread-guide and cause the deposition of the thread in cross-wound layers.

This manner of collecting the thread in high speed spinning has proved to offer particular ad vantages, since the faults caused by the reciprocating thread-guide are thereby completely avoided. While in the known spinning processes the difficulties increase very rapidly with an increasing speed of spinning, it is surprising that the process of the invention has been found to operate at a spinning'velocity of 120 meters per minute even better than at, for instance, 80 meters per minute; for the pendulous oscillations have at the higher spinning velocity a smaller amplitude owing to the formation of harmonics. In this manner there can be produced, even with very high speeds of draught, an artificial silk of unobjectionable quality in well formed durable windings.

Incarrying out the process it has been found advantageous to use a spinning bath having a rapid coagulating action. It is to be recommended that in carrying out the process there should be used a spinning bath containing besides sulfuric acid and sodium sulfate a salt of a polyvalent metal, for example, zinc sulfate, magnesium sulfate or aluminium sulfate.

The following examples illustrate the invention: v

Example 1 For a viscose thread with a titer of 180 den. prepared in a spinning bath having a specific weight of 1.4 and spun at a speed of 60 in. per minute, the resonance effect is obtained by giving the measures a, b, c, d of Figs. 1 and 1a the following values:

a=725 mm. b =95 mm. c=80 mm. d=50 mm.

the cake obtained after 6 hours spinning had the following dimensions:

Thread package Freshlglggn acid Wasilieiaidand 190 mm 178 mm. 100 mm 78 mm. 92 mm 51 mm. 1,270 grams 400 grams. 0.723 gram/cm 0.360 gram/cc.

Total titer 180 deniers Single titer deniers Length of thread 20,000 meters Example 2 When spinning a viscose thread having a titer of 300 deniers at the same speed in a spinning bath of the same specific weight the values of a, b, c and d are the following:

a=780 mm. b: 150 mm. c=70 mm. d=50 mm.

the cake obtained after 6 hours spinning had the Length of the thread Example 3 Spinning solution Spinning bath i Titer Draught Travel of thread in precipitating bath Device for removing precipitating liquid from threads Device for threads Speed of rotation of the plate collecting Planetary motion of the plate Distance of the middle point of the roller from the surface of the plate Lateral displacement of the point at which the thread leaves the roller with respect to the axis of the planetary drive Nature of pendulous oscillation.

Figs. 5 and 6 show a finished cake.

Viscose containing 7-8 per cent of cellulose and 6-7 per cent of sodium hydroxide 123 per cent of sulfuric acid, 18 per cent of sodium sulfate and per cent of, mag nesium sulfate 180/36 120 meters per minute 70 centimeters 2 glass rods of 5 mm. diameter at distances of 10 and 30 mm. above the surface of the bath Plate actuated by planetary drive 224.6 E. P. M.

110 R. P. M.

60 mm. backwardly and 300 mm. sideways The freely hanging length of thread executes an oscillation showing two'nodes As seen from these figures in practice the inner and the outer border of the cake may show a slight deformation. The outer, upper edge of the cake is generally somewhat rounded whereas the inner,

upper border may be somewhat raised. The walls of the cake are perfectly smooth and vertical on the plate.

The diameter of the cake is determined by the 5 speed at which the plate is rotated and the speed at which the thread is supplied. The mean diameter of the cake (see the dotted line in Fig. 2) is equal to speed at which the thread is supplied 1r number of revoultions of the plate Bobbin spinning Centrifugal spinning Plate spinning 100 grams 165 grams 500 grams 6, 000 meters 10, 000 meters 30, 000 meters which is drafted for a titer of 150 deniers.

The process according to this invention obviously is not limited to spinning viscose silk as shown in the examples but is adapted for spinning spinning solutions according to the wet spinning process quite generally. Thus, there may be spun solutions of cellulose acetate or another cellulose derivativeor there may be spun solutions of fibroin according to the wet spinning process. 7

What we claim is:

1. A process of producing artificial silk which comprises ejecting a spinning solution into a precipitating bath, guiding the coagulated thread around a rotating roller, rotating said roller at a peripheral speed of at least meters per minute, causing the thread to fall on a plate, rotating said plate at a speed so that a point of the plate at a substantial distance from the center of rotation has the same peripheral velocity as said roller, giving the plate an additional reciprocating movement so that at most one reciprocation occurs on half a revolution of the plate and adjusting the free length of the thread between the point at which the thread leaves the roller and the point at which the thread falls on the rotating plate so that the natural vibrations of the thread are in resonance with the reciprocating movement and a cake which needs no support is formed.

2. A process of producing artificial silk which comprises ejecting a spinning solution into a precipitating bath, guiding the coagulated thread around a rotating roller, rotating said roller at a peripheral speed of mms. per minute, causing the thread to fall on a plate, rotating said plate at 224.6 revolutions per minute, giving the plate an additional planetary motion of 110 revolutions per minute and adjusting the distance of the middle-point of the roller from the surface of the plate to 800 mms., adjusting the reciprocatory movement to a Width of 50 mms., adjusting the lateral displacement of the point at which the thread leaves the roller with respect to the axis of the planetary drive 60 mms. backwardly and 300 mms. sideways, and adjusting the supplied quantity of viscose to a final titer of deniers.

EMIL HUBERT. HANS DANNENBERG. 

